statistic : organizing data raw data information obtained by observing values of variable. frequency...
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STATISTIC : ORGANIZING DATA
Raw Data
Information obtained by observing values of variable.
Frequency distribution
List all categories and the number of elements that belong to each categories
Relative frequency
Obtained by dividing the frequency for a category by the sum of all the frequenciesThe sum of the relative frequencies will always equal one
Percentage
Obtained by multiplying the relative frequency for that category by 100
See Table 2.0
STATISTIC : ORGANIZING DATA
CATEGORY FREQUENCY RELATIVE
FREQUENCY
PERCENTAGE
Rape 2 2/25=0.8 0.8 x 100 = 8%
Robbery 3 3/25=0.12 0.12 x 100 = 12%
Burglary 3 3/25=0.12 0.12 x 100 = 12%
Arson 3 3/25=0.12 0.12 x 100 = 12%
Murder 3 3/25=0.12 0.12 x 100 = 12%
Theft 8 8/25=0.32 0.12 x 100 = 12%
Manslaughter 3 3/25=0.12 0.12 x 100 = 12%
Total 25 1.00 100%
Table 2.0
STATISTIC : ORGANIZING DATA
Bar graph
Graphs composed of bars whose height are the frequencies of different categories
Figure 2.0
Pie Chart
Used to graphically display qualitative data. A circle divided into portions thatrepresent relative frequency or percentages belonging to each categories.
Figure 2.1
Histograms
Graph that displays the classes on the horizontal axis and the frequencies of classes on the vertical axis (x, y). Although is similar to bar graph a histogramutilizes classes or intervals and frequencies while bar graph utilizes categories and frequencies.
Figure 2.2
STATISTIC : ORGANIZING DATA
Class limits, Class Boundaries, Class Marks, And Class Width
Frequency Distributions
When forming a frequency distribution, these general guidelines shouldBe followed
(i) The number of classes should be between 5 and 15 (ii) Each data value must belong to one, and only one, class (iii) When possible all classes must be in equal width
See Table 2.1
STATISTIC : ORGANIZING DATA
Frequency Distributions
Score/ Class Limits
Frequency Lower Limit
Upper Limit
Class Boundaries Class Width Class Marks
80-94 8 80 94 79.5-94.5 15 87.0
95-109 14 95 109 94.5-109.5 15 102.0
110-124 24 110 124 109.5-124.5 15 117.0
125-139 16 125 139 124.5-139.5 15 132.0
140-154 13 140 154 139.5-154.5 15 147.0
Boundaries
If the lower class limit for second class, 95, is added to the upper class limitfor the first class 94, and the sum divided by 2 the upper boundary and lowerboundary for the second class is determined.
Class Marks
If the lower class limit is added to the upper class limit for any class and the sum dividedby 2, the class mark is obtained.
Table 2.1
Camping 29%
Swimming 32%
Horse Riding 39%
Figure 2.1
A B C
Figure 2.0
10
20
30
40
50 Number of students for each grade in a Class
Types of Most Favored Hobbies and the percentages
STATISTIC : ORGANIZING DATA
Frequency Distributions
Figure 2.2
1
2
3
4
5 Price for 1 liter mineral water in several outlets
2.55 2.752.65 2.85
Price
Frequency
CATEGORY FREQUENCY RELATIVE
FREQUENCY
PERCENTAGE
India 2
China 5
Japan 10
Malaysia 10
Australia 4
Indonesia 4
Total
Exercise 1 : Fill the empty spaces with the required details
Create a pie chart using the details you’ve got from the table above
Exercise 2 : Fill the empty spaces with the required details
Cholesterol Cholesterol valuevalue
FrequencyFrequency Lower Lower limitlimit
Upper Upper LimitLimit
Lower Lower boundaryboundary
Upper Upper boundaryboundary
Class markClass mark
170-189170-189 33
190-209190-209 1010
210-229210-229 1717
230-249230-249 1313
250-269250-269 22
Create a Histogram with the answers you get from the filled table above